| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 398159000 | Reducing distortion or dispersion | 42 |
| 20080226302 | CHROMATIC DISPERSION COMPENSATION SYSTEM AND METHOD - Dispersion compensation is provided in an optical transmission system. An optical line couples first and second transceivers, and a plurality of amplifiers coupled to the optical line are spaced throughout the optical line with variable span distances. A plurality of dispersion compensation modules include a coarse granularity fiber, a connector, and a fine granularity fiber. A memory is associated with the dispersion compensators to provide information related to the value of the dispersion compensation. | 09-18-2008 |
| 20080226303 | DISPERSION-MANAGED OPTICAL TRANSMISSION SYSTEM - An optical transmission system that alleviates waveform distortions due to nonlinear effects in fibers. A transmitter sends WDM signals to a receiver over a dispersion-managed optical transmission line with in-line optical repeaters. The transmission line is divided into a plurality of dispersion compensation intervals each composed of a main segment and a compensation segment. Chromatic dispersion is managed such that the dispersion compensation intervals have a non-zero net dispersion at every boundary point between them, or such that the number of zero-dispersion boundary points is reduced. The main segment is a series of repeater sections with negative dispersion, while the compensation segment is a single repeater section with positive dispersion. Non-uniform distribution of net chromatic dispersions over the transmission length is achieved by combining repeater section with different average dispersions, dispersion compensation intervals with different numbers of repeater sections, or repeater sections with different span lengths. | 09-18-2008 |
| 20080260394 | Method and apparatus for dispersion mitigation in optical links - An optical communications system includes an optical transmitter that generates a modulated optical signal at an output. The modulated optical signal propagates through an optical link where the dispersion of the optical link is imprinted onto an optical spectrum of the modulated optical signal. A demodulator receives the modulated optical signal and filters at least a portion of the optical spectrum with the imprinted dispersion of the optical link, thereby mitigating effects of dispersion in the modulated optical signal and generating a demodulated optical signal at an output. An optical detector generates an electrical data signal from the demodulated optical signal. | 10-23-2008 |
| 20090080902 | DISPERSION COMPENSATION CONTROLLING APPARATUS AND METHOD FOR SEARCHING FOR AMOUNT OF DISPERSION CONTROL - In order to enhance dispersion control, the apparatus includes a dispersion controller; a quality index generator generating a quality index representing a quality of an optical signal output from the dispersion controller; and a searching unit searching for an amount of dispersion control applying to the dispersion controller which amount optimizes the quality index, wherein the searching unit includes a splitting-half searching unit roughly searching, in a splitting half method, a range in which dispersion is controllable by the dispersion controller for an amount of dispersion control such that the quality index generated by the quality index generator becomes preferable, and a sweep searching unit thoroughly searching, by sweeping, a limited range based on the amount of dispersion searched by the splitting-half searching unit for an amount of dispersion control that optimizes the quality index generated by the quality index generator. | 03-26-2009 |
| 20090097860 | Optical Dispersion Compensation - A method of providing dispersion compensation includes providing a dispersion signal indicative of an amount of dispersion for at least one channel of a multi-channel optical signal. A dispersion compensator is controlled in accordance with the dispersion signal to optically compensate for the dispersion of the optical signal. | 04-16-2009 |
| 20090190933 | DISPERSION AND NONLINEAR COMPENSATOR FOR OPTICAL DELIVERY FIBER - A system for dispersion compensation in a terahertz system includes an optical fiber configured to transmit an optical pulse, a compensator optically coupled to the optical fiber, the compensator configured to compensate for a dispersion of the optical pulse caused as the optical pulse propagates through the optical fiber, and an optically induced terahertz device optically coupled to the compensator, whereby the optically induced terahertz device is configured to transmit or receive terahertz radiation. | 07-30-2009 |
| 20090202255 | ABSTRACT OPTICAL RECEIVER WITH AUTOMATIC DISTORTION CANCELLATION - An optical receiver includes closed-loop composite second order (CSO) distortion correction logic. An optical communication system includes a transmitter comprising open-loop composite second order (CSO) distortion correction logic, and a receiver comprising closed-loop composite second order (CSO) distortion correction logic. | 08-13-2009 |
| 20090245809 | Optical transmission system - An optical transmission system capable of efficiently reducing waveform distortion of an optical signal. A transmitting-side distortion compensation coefficient storage of a transmitting station stores transmitting-side distortion compensation coefficients for compensating for waveform distortion of an optical signal to be transmitted to a receiving station. A transmit signal processor performs distortion compensation on the optical signal on the basis of a suitable transmitting-side distortion compensation coefficient stored in the transmitting-side distortion compensation coefficient storage. A transmitter transmits the distortion-compensated signal to a transmission path. A receiver of the receiving station receives the optical signal from the transmission path. A receiving-side distortion compensation coefficient storage stores receiving-side distortion compensation coefficients for compensating for waveform distortion of the optical signal received by the receiver. A received signal processor performs distortion compensation on the received optical signal on the basis of a suitable receiving-side distortion compensation coefficient. | 10-01-2009 |
| 20090324247 | OPTICAL MODULATOR - The present invention relates to an optical modulator that generates quaternary amplitude modulated light without inter-symbol-interference by splitting input light into three optical paths, generating a continuous wave signal in a first optical path, generating binary phase modulated lights using a single drive MZ type optical phase modulator in second and third optical paths, and interfering them at in-phase and at field amplitude 1:a:b. | 12-31-2009 |
| 20100014873 | Adaptive non-linearity compensation in coherent receiver - The invention relates to optical communication, in particular to compensation of non-linear distortions incurred in high bit-rate optical communication systems. A method and system for compensating self-phase modulation at an optical receiver of an optical transmission system using polarization division multiplexing and a modulation scheme with constant amplitude is proposed. The method comprises the step of performing a phase modulation on a received signal, wherein the received signal comprises two signal components associated with two orthogonal polarizations, each component comprising an in-phase sub-component and a quadrature-phase sub-component, thereby spanning a four-dimensional space. The phase modulation is determined by evaluating an error signal which depends on the distance in the four-dimensional space between the received signal after the phase modulation and a four-dimensional sphere defined by target constellation points of the optical transmission system. | 01-21-2010 |
| 20100028020 | Multimode Optical Fibers - A multimode optical fiber has an equivalent modal dispersion value (DMD | 02-04-2010 |
| 20100046961 | DISTORTION COMPENSATOR, OPTICAL RECEIVER, DISTORTION COMPENSATOR AND OPTICAL RECEIVER CONTROLLING METHODS, AND OPTICAL TRANSMISSION SYSTEM - A distortion compensator, an optical receiver and a transmission system including an operation selectively compensating for linear waveform distortion exerted on an optical signal via a plurality of distortion compensators and compensating for nonlinear waveform distortion exerted on the optical signal using nonlinear distortion compensators. | 02-25-2010 |
| 20100092181 | LOW CONVERSION RATE DIGITAL DISPERSION COMPENSATION - A method of suppressing effects of aliasing in a system for digitally processing a high speed signal having a symbol rate of 1/T. The high speed signal is sampled at a fractional multiple (N) of the symbol rate, wherein 1| 04-15-2010 | |
| 20100098434 | METHOD FOR DETERMINING VALUE OF CHROMATIC DISPERSION COMPENSATION - A method for determining a value of chromatic dispersion compensation in an optical network including a plurality of nodes connected by at least one transmission line, the plurality of nodes including a plurality of dispersion compensators, the optical network including a plurality of wavelength paths between the optional nodes, the method includes determining a compensation value of the dispersion compensators in the optical network by the computer, the compensation value selecting that an error between the object value of the residual chromatic dispersion in accordance with of the first end node of the first path and the permissible value of the residual chromatic dispersion of the first end node of the first path is least, and the value of the residual chromatic dispersion of the first end is in the permissible value of the residual chromatic dispersion of the second end node of the second path. | 04-22-2010 |
| 20100142973 | SEMICONDUCTOR LASER WITH LOW RELATIVE INTENSITY NOISE OF INDIVIDUAL LONGITUDINAL MODES AND OPTICAL TRANSMISSION SYSTEM INCORPORATING THE LASER - A semiconductor laser comprises an electrically isolated active section and at least one noise reducing section and operates on a ground state transition of a quantum dot array having inhomogeneous broadening greater than 10 nm. The laser preferably emits more than 10 optical modes such that a total relative intensity noise of each optical mode is less than 0.2% in the 0.001 GHz to 10 GHz range. The spectral power density is preferably higher than 2 mW/nm. An optical transmission system and a method of operating a quantum dot laser with low relative intensity noise of each optical mode are also disclosed. | 06-10-2010 |
| 20100158537 | PROPAGATION APPARATUS AND DISPERSION VALUE SETTING METHOD - A propagation apparatus includes a plurality of dispersion compensation execution units which accept a signal of a single wavelength from a wavelength-multiplexed signal which is received and execute dispersion compensation on the signal by inputting the accepted signal to a tunable dispersion compensator with an adjusted dispersion value, and a dispersion value calculation unit which acquires each dispersion value adjusted by the plurality of the dispersion compensation execution units, approximates the dispersion value of the wavelength assigned to a newly built line by using the acquired dispersion values whose signal error rates are in a tolerable range, and sets the approximated dispersion value as an initial value in the tunable dispersion compensator of the newly built line. | 06-24-2010 |
| 20100196017 | DISTORTION COMPENSATING APPARATUS, OPTICAL RECEIVING APPARATUS, AND OPTICAL TRANSMITTING AND RECEIVING SYSTEM - A distortion compensating apparatus which compensates for distortion in a waveform of a received light signal through a digital signal processing includes a plurality of fixed amount compensators which compensate for the distortion in the waveform at respective given compensating amounts. The combination of operating states of the plurality of fixed amount compensators is changed by on/off switching of each of the plurality of fixed amount compensators, and the plurality of fixed amount compensators are cascaded. | 08-05-2010 |
| 20100266291 | System and Method for Coherent Detection of Optical Signals - An optical communication system ( | 10-21-2010 |
| 20100316392 | TUNABLE DISPERSION COMPENSATION APPARATUS, OPTICAL RECEPTION MODULE AND METHOD - An apparatus includes: a first dispersion compensator that is arranged on an optical path between an input port and an output port, that has a dispersion compensation band, and that substantially compensates a chromatic dispersion to signal light by using a variable amount of dispersion compensation, a second dispersion compensator that is arranged on the optical path, that has a dispersion compensation band different from the dispersion compensation band of the first dispersion compensator, and that substantially compensates the chromatic dispersion to the signal light by using a variable amount of dispersion compensation and a controller that controls the first dispersion compensator in accordance with the value of chromatic dispersion to be compensated and that controls the amount of dispersion compensation and the dispersion compensation band in the second dispersion compensator in association with the amount of dispersion compensation in the first dispersion compensator. | 12-16-2010 |
| 20100329694 | ELECTRICAL DOMAIN SUPPRESSION OF LINEAR CROSSTALK IN OPTICAL COMMUNICATION SYSTEMS - The present disclosure provides electrical domain suppression of linear crosstalk in optical communication systems using single-carrier implementations. This electrical domain suppression applies spectral shaping in the electronic radio frequency (RF) domain. Advantageously, spectral shaping in the electronic RF domain transfers system complexity from the bulk optical domain into the highly integrated CMOS (or equivalent) domain. The spectral shaping can include electronic circuitry including an electrical filtering block and a signal linearization block prior to optical modulation. The electrical filtering block suppresses coherent interference terms and can include an RF-domain low pass filter. The signal linearization block linearizes modulator response to compensate spectral regrowth due to nonlinear mixing in the modulator. | 12-30-2010 |
| 20100329695 | DISPERSION SLOPE COMPENSATION AND DISPERSION MAP MANAGEMENT SYSTEMS AND METHODS - The present disclosure relates to dispersion slope compensation and dispersion map management systems and methods in an optical network utilizing a reconfigurable optical add-drop multiplexer (ROADM) with a plurality of different values of dispersion compensation modules (DCMs). The DCMs form a dispersion compensation ladder at certain intermediate nodes in the optical network to provide dispersion slope compensation and dispersion map management. The reconfigurable routing structure of the ROADM enables these intermediate nodes to route individual wavelengths to any one of the DCMs as required for the particular path of the wavelength. Advantageously, the present invention removes the requirement for banded compensation at receiver nodes and allows for dispersion map management at intermediate points along a fiber route as opposed to bulk compensation at the receiver. | 12-30-2010 |
| 20110206382 | METHOD AND A SYSTEM WITH DISTORTION COMPENSATION - The invention relates to a method and an apparatus for distortion compensation of signals transmitted via a bidirectional link between a client device and a host device, said method comprising the steps of performing a post-distortion-compensation for an upstream signal received by the host device on said bidirectional link by adjusting post-compensation parameters of a post-compensation unit of said host device and transforming the adjusted post-compensation parameters into pre-compensation parameters of a pre-compensation unit of said host device which performs a pre-distortion compensation for a downstream signal transmitted by said host device via said bidirectional link to said client device. | 08-25-2011 |
| 20110249979 | TUNABLE DISPERSION COMPENSATOR CONFIGURED FOR CONTINUOUS SETPOINT CONTROL - A tunable dispersion compensator (TDC) is tuned from a first dispersion setpoint to a second dispersion setpoint while maintaining continuity of the dispersion. The dispersion tuning follows a pre-determined trajectory in the time domain, so that continuity of the optical dispersion across the channel optical bandwidth is maintained while minimizing all other TDC-induced optical impairments during a tuning period | 10-13-2011 |
| 20110311233 | AUTOMATED DISPERSION COMPENSATION OVER A BROAD WAVELENGTH RANGE FOR COHERENT OPTICAL PULSES - The present application is directed to an apparatus and method for the automated compensation of dispersion over a broad wavelength range for coherent optical pulses. In one embodiment, the present application discloses an automatic dispersion compensating optical apparatus configured to change chirp introduced into an optical signal by an optical system in optical communication with the dispersion compensating optical apparatus and includes at least one wavelength-tunable source of coherent optical pulses configured to output at least one optical signal, at least one dispersion compensation device configured to receive the optical signal from the coherent source, and at least one controller in communication with the dispersion compensation device and configured to adjust chirp introduced into the optical signal by the dispersion compensation device as the wavelength of the optical signal is varied. | 12-22-2011 |
| 20110318019 | COMMUNICATION TRANSMISSION SYSTEM WITH OPTICALLY AIDED DIGITAL SIGNAL PROCESSING DISPERSION COMPENSATION - The present disclosure is directed to managing dispersion compensation in optical transmission line utilizing single mode fiber with no in-line dispersion compensation. A communication system terminal includes one or more dispersion compensation modules configured to compensate for at least a portion of optical dispersion associated with optical data signals supplied from the transmission line. A receiver communicatively coupled to the transmission line includes a digital signal processor configured to compensate for an additional portion of dispersion associated with the optical data signals converted to electrical signals by the receiver. | 12-29-2011 |
| 20120263479 | OPTICAL NETWORK COMMUNICATION SYSTEM WITH VARIABLE OPTICAL ATTENUATION AND METHOD OF OPERATION THEREOF - A method of operation of an optical network communication system includes: coupling an input fiber; receiving light with a lens from the input fiber, the light having a predetermined amount of mode-field-diameter dispersion; tilting a mirror for reflecting the light after the light is transmitted through the lens; and positioning an output fiber for retransmitting the light from the lens after the light is reflected from the mirror for wavelength-dependent-loss reduction. | 10-18-2012 |
| 20120269519 | Apparatus and Method to Calculate a Noise Figure of an Optical Amplifier for Wavelength Channels in a Partial-Fill Scenario to Account for Channel Loading - An apparatus comprising a processor configured to calculate a noise figure of an optical amplifier for a plurality of selected wavelength channels in a partial-fill scenario that accounts for channel loading. The noise figure is calculated using a plurality of corresponding noise figure correction values at a plurality of wavelengths based on an effective number of channels. | 10-25-2012 |
| 20120281988 | Optical Transmission System - In an optical multilevel transmitter ( | 11-08-2012 |
| 20130272718 | System And Method For Nonlinear Self-Filtering Via Dynamical Stochastic Resonance - A system and method for filtering and enhancing signals from a noise background based on the nonlinear interaction of waves. The system and method amplify low-level signals, hide information in the signals, and then nonlinearly recover the signals. With the present invention, this can be performed for both spatial beams and temporal pulses. The signal self-filters and self-amplifies at the expense of the surrounding noise via the nonlinear medium. | 10-17-2013 |
| 20130272719 | Method and Apparatus for Compensating Nonlinear Distortions in Intensity Modulation-Direct Detection System - The embodiments of the present invention provide a method and an apparatus for compensating nonlinear distortions in an intensity modulation-direct detection (IM-DD) system; wherein the method comprises: calculating, according to nonlinear coefficients and differences between values of an input signal at different time, nonlinear distortions of the input signal, so as to eliminate the nonlinearity distortions. By applying the method and the apparatus provided by the embodiments of the present invention, nonlinear cost of the IM-DD system can be effectively reduced, thereby improving the system capacity. | 10-17-2013 |
| 20130315607 | LOW COST DIRECT MODULATION AND COHERENT DETECTION OPTICAL OFDM - System and method for compensating distortions introduced by an optical channel and by at least one directly modulated transmitting laser that transmits a modulated optical signal that carries data to a receiving end over the optical channel. At the receiving end, the transmitted signal is received by a coherent receiver that processes the received signal by compensating the distortions introduced by the optical channel by applying, on the received signal, an operator being capable of essentially compensating for all fiber distortions in the optical channel; compensating the non-linear phase distortions and/or statistical phase distortions introduced by the directly modulated transmitting laser by applying, on the processed signal obtained after compensating the fiber distortion, a non-linear operator being the extraction of the absolute value of the compensated signal; and extracting the data carried by the processed signal, from the absolute value of the processed signal obtained after compensating the non-linear phase distortions and/or statistical phase distortions, thereby demodulating the processed signal. | 11-28-2013 |
| 20140003822 | OPTICAL COMMUNICATION APPARATUS AND METHOD | 01-02-2014 |
| 20140341592 | APPARATUS AND METHOD OF COMPENSATING FOR COMPACT DIGITAL DOMAIN CHROMATIC DISPERSION - A method and apparatus of compensating for compact digital domain chromatic dispersion. The distortion of an optical signal due to chromatic dispersion is compensated by a digital signal processing in the electrical domain, either prior to the optical transmitter or following the receiver. The circular coefficient approximation and sub-band processing reduce the amount of computations to execute a given level of chromatic dispersion compensation compared to a direct finite impulse response filter implementation. | 11-20-2014 |
| 20140369694 | DISPERSION DOMINATED OPTICAL COMMUNICATIONS SYSTEM AND METHOD OF PRE-DISPERSION - Communication transmission system and method are disclosed based on introducing a large pre-dispersion of optical signal before launching the signal into an uncompensated communication system. The pre-dispersion has the same sign as dispersion of a transmission fibre. The aim of the method is to improve the transmission quality and simplify the digital signal mitigation of nonlinear impairments after the transmission. In the preferred embodiment, the optical system is a coherent communications system with any symbol rate, modulation format and/or carrier wavelength. | 12-18-2014 |
| 20150093119 | SYMBOL SPACED ADAPTIVE MIMO EQUALIZATION FOR ULTRA HIGH BIT RATE OPTICAL COMMUNICATION SYSTEMS - System and method for equalizing a high bit rate optical communication channel in a symbol spaced adaptive Multiple-In-Multiple-Out (MIMO) system, where the optical communication channel carries a signal that is sampled at a symbol rate. Accordingly, Anti Aliasing Filtering (which introduces distortions in the form of Deterministic Inter Symbol Interference D-ISI) is applied in a MIMO channel, in order to reduce the aliasing effect associated with symbol rate sampling. The Polarization Mode Dispersions introduced in the optical communication channel are solely compensated by a MIMO Equalizer, which ignores the Deterministic ISI (D-ISI) distortion. Then the Deterministic ISI (D-ISI) distortion is solely compensated by an independent Deterministic Equalizer (DE). | 04-02-2015 |
| 20150104190 | OPTICAL TRANSMISSION CIRCUIT, OPTICAL TRANSMISSION DEVICE, AND OPTICAL TRANSMISSION SYSTEM - A driving element which performs driving according to a level of a voltage signal to be transmitted optically, a modulation current driving circuit configured to supply a modulation current modulated by the driving element to a light source for optical communication configured to convert a current signal into light and to output the light, and a constant current supply circuit configured to supply a constant current to the light source for optical communication are included. Then, when the voltage signal is at a first level, the driving element is turned on and the modulation current driving circuit supplies the modulation current to the light source for optical communication. When the voltage signal is at a second level, the driving element is turned off and the modulation current driving circuit stops supplying the modulation current. The present technique can be applied, for example, to an optical transmission system. | 04-16-2015 |
| 20160028480 | OPTICAL TRANSMISSION SYSTEM, OPTICAL TRANSMITTER, OPTICAL RECEIVER, AND OPTICAL TRANSMISSION METHOD - An optical transmitter ( | 01-28-2016 |
| 20160036527 | Method and System for Optical Impairment Mitigation for High-Speed Optical Communication Systems - A method and system for simultaneous mitigation of optical impairment from both equalizer-phase noise interaction (EPNI) and fiber nonlinear effects (FNE) is disclosed. In one embodiment, the method is directed to simultaneous mitigation of optical impairment from both equalizer-phase noise interaction (EPNI) and fiber nonlinear effects (FNE) using a fast-adaptive multi-tap digital filter. | 02-04-2016 |
| 20160099777 | Optical Receiver with Optical Transmitter-Specific Dispersion Post-Compensation - An apparatus comprising a frontend configured to convert an optical IM signal associated with a remote optical transmitter into a plurality of analog electrical signals, determine a plurality of DC offsets for the analog electrical signals, remove the DC offsets from the analog electrical signals to produce a plurality of DC-free analog signals, and convert the DC-free analog signals into a plurality of DC-free digital signals, and a DSP unit coupled to the frontend and configured to perform fiber dispersion compensation on the DC-free digital signals according to a dispersion value associated with the remote optical transmitter to produce a plurality of DC-free compensated digital signals, and add the DC offsets to the compensated digital signals to produce a plurality of DC-restored compensated digital signals. | 04-07-2016 |
| 20160105297 | JOINT TRANSMITTER AND RECEIVER MAP ALGORITHM FOR ENHANCING FILTERING TOLERANCE IN A BANDWIDTH-LIMITED SYSTEM - A system for optimizing signal quality in an optical communication system is provided including a transmitter for converting digital signals to optical signals, the transmitter including a transmitter digital signal processing chip including a pre-distortion logic and a transmitter look-up table (LUT). A receiver is operatively coupled to the transmitter for receiving and converting the optical signals from the transmitter to digital signals. The receiver includes a receiver digital signal processing chip including a correction logic and a receiver look-up table (LUT). The transmitter LUT is constructed by scaling the receiver LUT by a weight factor and is iteratively updated based on a weighted sum of the receiver LUT. | 04-14-2016 |
| 20160164610 | OPTICAL COMMUNICATION SYSTEM, OPTICAL RECEIVER, OPTICAL RECEIVER CONTROL METHOD, AND NON-TRANSITORY COMPUTER READABLE MEDIUM - Present invention provides an optical communication system that controls reception sensitivity of an optical receiver. The communication system ( | 06-09-2016 |
| 20180026719 | OPTICAL RECEIVER WITH OPTICAL TRANSMITTER-SPECIFIC DISPERSION POST-COMPENSATION | 01-25-2018 |
